S C Ambrosio | PubMed Health

PubMed1984

Abnormal keratohyalin-like forms in leukoedema.

Electron microscopic, histochemical and light-microscopic studies were carried out on biopsy specimens of 12 cases of leukoedema and on the desquamated epithelial cells of a further 50 examples. For comparison, similar observations were made of 4 examples of healthy cheek mucosa and 29 cases of a variety of pathological conditions of the oral mucosa. Only in leukoedema were a series of structures encountered which consisted of an aggregation of ribosomes and electron dense masses, or a network of electron-dense material, or an electron-dense network with a central dense core or a solid body with a few central cavities. Histochemical stains and RNA extraction studies showed that they are probably abnormal forms of keratohyalin granules and that ribosomes is an important component of their composition.

Cytoplasmic Granules↗

PubMed1983

Leukoedema: ultrastructural and histochemical observations.

The ultrastructural features of 12 cases of leukoedema were investigated and compared with clinically normal buccal mucosa. Histochemistry was undertaken to try to resolve some of the observed ultrastructural changes. The characteristic "intracellular edema" of the epithelial cells in leukoedema is due to vacuolation in the cytoplasm of cells. Abnormal mitochondria were observed in these cells. The vacuoles contained a granular material somewhat like clumped glycogen granules, but histochemistry failed to identify this material as glycogen. Towards the surface of the epithelium, the vacuolated cells collapsed into a compact layer of flattened cells. The outer cells of this layer abruptly swelled again to form the characteristic superficial layer of "ballooning" cells of leukoedema. The latter cells were not vacuolated but contained remnants of organelles, membraned vesicles with remnants of organelles, keratohyalin granules and structures apparently related to keratohyalin granules. We propose that the vacuolation represents a limited reversible form of cellular degeneration resulting from cell damage and that impeded mitochondrial function may be the cause of the vacuolation. The superficial "ballooning" cells are degenerated cells. The flattening of the vacuolated cells into a compact layer and the presence of keratohyalin granules and keratohyalin-like structures in the superficial cells are regarded as features of an aborted form of keratinization.

Adolescent↗